Kerala: Plastic in fish a cause for concern

KOCHI: Though there is a growing awareness about the marine litter in coastal and territorial waters, the presence of microplastics in the guts of staple fishes like sardines and mackerels has become a cause for concern.
A review paper on ‘microplastics in fish’ in the Indian Journal of Fisheries by B Madhusudana Rao, a scientist at the Central Institute of Fisheries Technology (CIFT) said that there is a paucity of documented evidence on the adverse effect of micro-plastics on human health due to consumption of such fishes.

“Protocol for the determination of quantity of microplastics in fish flesh needs to be standardized. Likewise, the quantity of microplastics that would be considered as a food hazard also needs to be fixed. There is a need to perform risk analysis to categorize microplastic as a food hazard in fish meant for human consumption,” he said.
“We have begun testing and analyzing fish meat for microplastics as their consumption could have an impact on human health. But we need to conduct more research,” said Saly N Thomas, principal scientist, CIFT and member of the group of experts on the scientific aspects of marine environmental pollution.
“It is not possible to technically verify whether any particular fish species or a single specimen died due to the plastic in their bodies. But we do know that microplastics are found in phytoplanktons and small fishes which enter the body of bigger fishes,” said V Kripa, head of fisheries environment management division, the Central Marine Fisheries Research Institute (CMFRI).
A recent study by researchers at the Kerala University of Fisheries and Ocean Studies (KUFOS) on the Vembanad Lake and the coastal belt of Kochi found the presence of heavy macroplastic litter in the bottom sediments. The sediment includes both light microplastic materials such as plastic covers, plastic carry bags, among other things, to the tune of 8.04 tonnes/sq.km and heavy macroplastic items like plastic slippers, fishing gear materials, rexine sheets etc., which account for 47.88 tonnes per sq.km area of the bottom sediment. The discrepancy in the load of light and heavy macroplastics in the sediments may be since most of the light macroplastic litters might have been transported to the sea with the tide.
According to existing literature, microplastics when ingested by fish, may translocate across the gastrointestinal tract and gills and enter the circulatory system. Through blood circulation, microplastics reach different organs and muscles. Humans consuming microplastics-laden fish meat are vulnerable to the effects of microplastics. Microplastics physically attach to the skin and gills of the fish and the consumption of fish skin and gill tissue provides another route of transmission of microplastics to humans.
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